Polyvinyl siloxane (PVS) impression materials incorporating a polyether carbosilane wetting agent... more Polyvinyl siloxane (PVS) impression materials incorporating a polyether carbosilane wetting agent and mixed with an electronic mixing system (Pentamix) were clinically compared with traditionally delivered (i.e., automixed) PVS impression materials during routine use by 1,505 general and specialized dental practitioners evaluating more than 30,000 impressions. Each study participant selected 20 patients and used standard tooth-preparation procedures appropriate to the therapy required, supplied specific data on each case, and ultimately evaluated the marginal detail, fit, and success of the final restorations. The areas requiring evaluation upon completion of the final restorations were ranked between "excellent," "good," "poor," and "remake needed," among users of the PVS materials with the electronic mixing system. About 80% of the respondents rated the Pentamix system as easier to mix and deliver than the gun or hand-mixed systems and two thirds said it was faster to mix. The system also received high scores for hygienic delivery, ease of mixing, and clean-up.
Control of moisture is critical in the oral cavity to obtain the optimal properties of dental mat... more Control of moisture is critical in the oral cavity to obtain the optimal properties of dental materials and thus increase their longevity. The conventional rubber dam is a 6" x 6" latex sheet held in place with a separate frame. This study evaluated a new moisture control device that is self-supported by a rolled spring border. Twenty-four patients seen by 24 different dental operators and six dental assistants, with previous experience using the conventional rubber dam, participated. The study concluded that there was significant improvement in user acceptance and patient comfort with the use of this isolation device and, from the compilation of remarks from questionnaires, it was concluded that it was most effective for completion of anterior teeth restorations.
Learning indirect vision with a dental mirror is challenging and can be overwhelming for beginnin... more Learning indirect vision with a dental mirror is challenging and can be overwhelming for beginning dental students. The Jumpstart Mirror Trainer is a new device that allows students to become proficient with mirror use before the start of preclinic without requiring in-class practice sessions. The aim of this study, conducted in 2017, was to compare the effectiveness of the Jumpstart Mirror Trainer with the Mirroprep for teaching indirect motor skills. Forty-seven first-year dental students were randomized into three groups to use the Jumpstart Mirror Trainer, Mirroprep, or a control device for 15 minutes a day for ten days. To assess indirect motor skills improvement, students performed a maxillary cavity preparation before and after using their devices. A survey was used to assess students' comfort level with mirror skills and perceived helpfulness of the exercises. Forty students completed the study. The Jumpstart Mirror Trainer activities improved the students' scores significantly more than the Mirroprep activities (p=0.04) and the control device (p=0.006). Students in the Jumpstart Mirror Trainer group rated their device as being significantly more helpful than the control group rated its device in preparing them for the evaluation (p=0.001). There was no statistically significant difference in perceived helpfulness between the Mirroprep group and the control group (p=0.75). These results suggest that the Jumpstart Mirror Trainer may be able to improve students' indirect motor skills without requiring in-class practice sessions and to do so more effectively than other existing methods.
Although nitrous oxide (N(2)O) has been widely used since 1844, in recent years it has been impli... more Although nitrous oxide (N(2)O) has been widely used since 1844, in recent years it has been implicated in a number of serious health hazards such as reproductive, nerve, liver, and kidney disorders. The National Institute of Safety and Health (NIOSH) recommends a limit of 25 ppm for chronic exposure to N(2)O in the dental office. Our study monitored ambient N(2)O levels in the dental office. N(2)O levels were compared for procedures performed in open clinics and private operatories as well as with and without a gas-scavenging system. Measurements were taken in the Dental Breathing Zone (DBZ) and Dental Chair Foot (DCF) at regular intervals. A four- to eightfold increase in average N(2)O levels was noted in the DBZ for unscavenged versus scavenged procedures. A three- to fourfold increase for unscavenged versus scavenged procedures was similarly noted in the DCF. N(2)O were significantly higher in private operatories than in open clinics, due to limited room volumes and in the DBZ over the DCF, due to mask leakage and increased oral exhalation. Scavenged N(2)O levels for both operatory types did not meet NIOSH guidelines. In contrast to previous studies using any form of gas removal, our study shows a significant decrease in N(2)O level achieved with an adequate scavenger system. With only four states regulating the use of N(2)O, and with concern over its deleterious effects growing, additional states and the federal government are expected to enact legislation regulating the use of N(2)O in the near future.
Esthetic restorative materials require a bonding procedure in order to be durable and reliable. I... more Esthetic restorative materials require a bonding procedure in order to be durable and reliable. In order to accomplish this ideal, the bonding system must be biocompatible, bond indifferently to enamel and dentin, have sufficient strength to resist masticator forces, have mechanical properties close to those of tooth structures, be resistant to degradation in the oral environment and easy to use. This paper reviews the published literature on direct and indirect adhesive restorative materials.
This article compares the bleaching efficacy of a combined at-home and in-office system with that... more This article compares the bleaching efficacy of a combined at-home and in-office system with that of an in-office system alone. Twenty people participated in the study. Ten of these participants were treated with an in-office 35% carbamide peroxide bleaching product in 2 visits of 15 minutes each. The remaining participants were treated with a combination at-home and in-office system that included a 15% carbamide peroxide at-home bleaching agent. After 5 days of treatment, the participants using the combination system demonstrated increased tooth whitening compared to those using the in-office system alone. Based on the sample size (20 patients), statistical significance was achieved.
A randomized, single-center, double-blind, parallel-group, placebo-controlled trial evaluated the... more A randomized, single-center, double-blind, parallel-group, placebo-controlled trial evaluated the whitening efficacy and safety of 2-week, twice-daily use of a 5.3% hydrogen peroxide tooth-bleaching gel delivered on polyethylene film. Efficacy was based on change in Vita shade scores from baseline to the end of treatment. Thirty-three patients in each group completed treatment. Use of the peroxide-containing gel led to a mean change in baseline Vita shade score of -3.70 +/- 0.35, compared with a change of -0.87 +/- 0.24 after use of a placebo gel. After adjustment for baseline scores, the mean difference in shade change between the peroxide gel-treated group and placebo-treated group was -2.85 +/- 0.41 (P < 0.0001). Both treatments were generally well tolerated. The strips offer ease of use, comfort, and shorter duration of wear compared with other at-home bleaching systems.
Objective: The objective of this study was to evaluate the effect of a dental water jet on plaque... more Objective: The objective of this study was to evaluate the effect of a dental water jet on plaque biofilm removal using scanning electron microscopy (SEM). Methodology: Eight teeth with advanced aggressive periodontal disease were extracted. Ten thin slices were cut from four teeth. Two slices were used as the control. Eight were inoculated with saliva and incubated for 4 days. Four slices were treated using a standard jet tip, and four slices were treated using an orthodontic jet tip. The remaining four teeth were treated with the orthodontic jet tip but were not inoculated with saliva to grow new plaque biofilm. All experimental teeth were treated using a dental water jet for 3 seconds on medium pressure. Results: The standard jet tip removed 99.99% of the salivary (ex vivo) biofilm, and the orthodontic jet tip removed 99.84% of the salivary biofilm. Observation of the remaining four teeth by the naked eye indicated that the orthodontic jet tip removed significant amounts of calcified (in vivo) plaque biofilm. This was confirmed by SEM evaluations. Conclusion: The Waterpik dental water jet (Water Pik, Inc, Fort Collins, CO) can remove both ex vivo and in vivo plaque biofilm significantly.
The effects of nitrous oxide (N2O) on steady-state concentrations and turnover rates of catechola... more The effects of nitrous oxide (N2O) on steady-state concentrations and turnover rates of catecholamines in the olfactory bulb, hypothalamus, brain stem, hippocampus, striatum, thalamus, cerebral cortex, and spinal cord were determined in rats. Animals were exposed for 2 h to either 60% N2O or air. Immediately following exposure, all animals were injected intraperitoneally with alpha-methylparatyrosine (alphaMPT), a competitive inhibitor of tyrosine hydroxylase, and sacrificed at 0, 30, or 90 min postinjection. Brain catecholamine concentrations were determined using high-performance liquid chromatography coupled with electrochemical detection (HPLC-EC). Results indicate that N2O exposure significantly elevates steady-state concentrations of norepinephrine (NE) in the hypothalamus and striatum yet decreases amine levels in the brain stem region. Steady-state levels of dopamine (DA) were not significantly altered in any region of the CNS by N2O exposure. Acute exposure to N2O also resulted in significant decreases in the turnover rate of NE in the brain stem, yet it increased turnover of this amine in the olfactory bulb, hypothalamus, and striatum. Acute exposure to N2O resulted in a decreased turnover rate of DA in the hippocampus and striatum. In contrast, N2O appears to increase DA turnover in the olfactory bulb. These results indicate that acute exposure to N2O in rats causes region-specific alterations in steady-state levels and turnover rates of DA and NE within the central nervous system.
Acrolein was examined as an alternative fixative to formaldehyde for immunocytochemicab localizat... more Acrolein was examined as an alternative fixative to formaldehyde for immunocytochemicab localization of neuropeptides in the rat brain. A brief (5 mm) vascular perfusion with a 5% acrolein solution allowed the identification of thyrotropin-releasing hormone (TRH), vasoactive intestinal peptide (VIP), somatostatin (SRIF), neurotensin (NT), methionine enkephalin (Menk), adrenocorticotropic hormone (ACTH), tyrosine hydroxylase (TH), and luteinizing hormone-releasing hormone (LHRH) in fibers and pen
Compendium of continuing education in dentistry, Jul 1, 2010
Questionnaires that focus on the fear of dental treatment typically include a narrow list of prev... more Questionnaires that focus on the fear of dental treatment typically include a narrow list of previous treatment-related factors. By omitting items concerned with psychologic, emotional, and interpersonal traits that impact treatment, practitioners often fail to gain additional valuable information on related anxiety issues. This study was undertaken to identify previously unrecognized or poorly discussed sources of fear and anxiety in patients seeking esthetic dental treatment. The Esthetic Clinic at Tufts University School of Dental Medicine recruited 62 participants who were asked to score their level of anxieties and concerns based on 24 different items on a 0 to 5 Likert scale. In addition, age, gender, and type of procedure in consideration were the only other variables recorded. The item that elicited the highest level of anxiety was &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;not feeling happy with my new smile.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; Thirty-eight respondents (61.3%) said they feel &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;markedly anxious&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;severely anxious&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; or answered &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;avoid completely.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; Concerns &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;that the outcome might look false and unnatural&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;that the dentist might not redo it if I am not satisfied with the outcome&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; both received 37 out of 62 (59.7%) similar responses. These results suggest obstacles to treatment exist not only in areas typically investigated but also in factors rarely discussed during the patient-practitioner encounter. The practitioner needs to consider a broader range of issues when addressing the patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s concerns.
Many studies have indicated that nitrous oxide (N2O) exposure results in specific effects on the ... more Many studies have indicated that nitrous oxide (N2O) exposure results in specific effects on the reproductive system, some of which are antigonadotropic. The neurochemical events regulating the pituitary-gonadal axis are probably influenced by N2O, but precise documentation is lacking. The effects of exposure to 30% N2O in air on the brain tissue concentrations of luteinizing hormone releasing hormone (LHRH), substance P (SP), met-enkephalin, and beta-endorphin and on beta-endorphin concentrations of the pituitary gland are described in this study. Female rats were exposed to either N2O or air for 8 hr a day over one estrous cycle, and the brain and pituitary tissues were collected and processed. Neuropeptide concentrations were measured by specific radioimmunoassays. Exposure to N2O resulted in significant elevation of LHRH in the preoptic area, with a concomitant decrease in SP. The SP concentration of the medial basal hypothalamus was significantly elevated in N2O-exposed animals. Exposure to N2O resulted in significant increases in met-enkephalin in the brainstem area and beta-endorphin in the pituitary. These results suggest that exposure to N2O alters the interactive neural system activity regulating gonadotropin secretion from the pituitary. The significance of increased met-enkephalin in the brainstem of N2O-exposed animals is not known.
The increasing demand for esthetically pleasing results has contributed to the use of ceramics fo... more The increasing demand for esthetically pleasing results has contributed to the use of ceramics for dental implant abutments. The aim of this study was to compare the biological response of epithelial tissue cultivated on lithium disilicate (LS2) and zirconium oxide (ZrO2) ceramics. Understanding the relevant physicochemical and mechanical properties of these ceramics will help identify the optimal material for facilitating gingival wound closure. Both biomaterials were prepared with 2 different surface treatments: raw and polished. Their physicochemical characteristics were analyzed by contact angle measurements, scanning white-light interferometry, and scanning electron microscopy. An organotypic culture was then performed using a chicken epithelium model to simulate peri-implant soft tissue. We measured the contact angle, hydrophobicity, and roughness of the materials as well as the tissue behavior at their surfaces (cell migration and cell adhesion). The best cell migration was o...
More important than any resin cement is the marginal fit and retentive nature of the ceramic rest... more More important than any resin cement is the marginal fit and retentive nature of the ceramic restoration to be bonded. Cementation should not be intended to compensate for poor dentistry, but to assist in producing superior aesthetic results. Responding to the demand for all-ceramic restorations, dental manufacturers continue to refine the resin cements used in luting for this modality. The ideal resin cement for ceramic restorations must demonstrate low viscosity; easy loading; a film thickness which facilitates complete seating high strength; and excellent wear resistance. This article reviews the available resin cements, with particular focus on a new type of initiator and stabilizer for light- and dual-cured resin cements.
The purpose of this study was to compare the wear, cement margin breakdown and bond strength of r... more The purpose of this study was to compare the wear, cement margin breakdown and bond strength of restorations following 6 to 12 months of simulated use in vitro of the Sonicare and a manual toothbrush. Extracted molar teeth with Class V hybrid composite resin restorations (n = 21) or with Class V gold inlays cemented with zinc phosphate cement were tested for wear and marginal integrity following brushing for a period that simulated 6 months of typical use. One-third of the molars in each group were brushed with the Sonicare and one-third were brushed with the manual brush. The remaining third served as non-treated controls. Toothbrushing was performed under a standardized load using a piston-action brushing machine. After brushing, the enamel, dentin/cementum and restorations were examined by light and scanning electron microscopy. There was no apparent wear of tooth structure or of restorative materials with either the Sonicare or the manual brush. There was a small loss of cement ...
Twenty-two family practice dentists, in a large metropolitan area, were recruited to act as indep... more Twenty-two family practice dentists, in a large metropolitan area, were recruited to act as independent examiners in a study to evaluate the compliance of their patients to accept a good oral hygiene regimen with the use of a fluoride dentifrice, containing hydrogen peroxide and baking soda, dispensed from a dual dispensing package. To evaluate compliance, the dentists attended an orientation seminar and were trained to assess gingival health using the CPITN periodontal probe. Each dentist evaluated the gingival health status of five to seven of his own patients, initially and after one and three months of product use following hygiene instruction and product assignment. One-hundred and thirty-one patients successfully completed the study. After one month of using the hydrogen peroxide/baking soda toothpaste, the mean reduction in bleeding sites was 53%; at three months the reduction was 62%. The hydrogen peroxide/baking soda dentifrice was well accepted by dentist and patient, and ...
Polyvinyl siloxane (PVS) impression materials incorporating a polyether carbosilane wetting agent... more Polyvinyl siloxane (PVS) impression materials incorporating a polyether carbosilane wetting agent and mixed with an electronic mixing system (Pentamix) were clinically compared with traditionally delivered (i.e., automixed) PVS impression materials during routine use by 1,505 general and specialized dental practitioners evaluating more than 30,000 impressions. Each study participant selected 20 patients and used standard tooth-preparation procedures appropriate to the therapy required, supplied specific data on each case, and ultimately evaluated the marginal detail, fit, and success of the final restorations. The areas requiring evaluation upon completion of the final restorations were ranked between "excellent," "good," "poor," and "remake needed," among users of the PVS materials with the electronic mixing system. About 80% of the respondents rated the Pentamix system as easier to mix and deliver than the gun or hand-mixed systems and two thirds said it was faster to mix. The system also received high scores for hygienic delivery, ease of mixing, and clean-up.
Control of moisture is critical in the oral cavity to obtain the optimal properties of dental mat... more Control of moisture is critical in the oral cavity to obtain the optimal properties of dental materials and thus increase their longevity. The conventional rubber dam is a 6" x 6" latex sheet held in place with a separate frame. This study evaluated a new moisture control device that is self-supported by a rolled spring border. Twenty-four patients seen by 24 different dental operators and six dental assistants, with previous experience using the conventional rubber dam, participated. The study concluded that there was significant improvement in user acceptance and patient comfort with the use of this isolation device and, from the compilation of remarks from questionnaires, it was concluded that it was most effective for completion of anterior teeth restorations.
Learning indirect vision with a dental mirror is challenging and can be overwhelming for beginnin... more Learning indirect vision with a dental mirror is challenging and can be overwhelming for beginning dental students. The Jumpstart Mirror Trainer is a new device that allows students to become proficient with mirror use before the start of preclinic without requiring in-class practice sessions. The aim of this study, conducted in 2017, was to compare the effectiveness of the Jumpstart Mirror Trainer with the Mirroprep for teaching indirect motor skills. Forty-seven first-year dental students were randomized into three groups to use the Jumpstart Mirror Trainer, Mirroprep, or a control device for 15 minutes a day for ten days. To assess indirect motor skills improvement, students performed a maxillary cavity preparation before and after using their devices. A survey was used to assess students' comfort level with mirror skills and perceived helpfulness of the exercises. Forty students completed the study. The Jumpstart Mirror Trainer activities improved the students' scores significantly more than the Mirroprep activities (p=0.04) and the control device (p=0.006). Students in the Jumpstart Mirror Trainer group rated their device as being significantly more helpful than the control group rated its device in preparing them for the evaluation (p=0.001). There was no statistically significant difference in perceived helpfulness between the Mirroprep group and the control group (p=0.75). These results suggest that the Jumpstart Mirror Trainer may be able to improve students' indirect motor skills without requiring in-class practice sessions and to do so more effectively than other existing methods.
Although nitrous oxide (N(2)O) has been widely used since 1844, in recent years it has been impli... more Although nitrous oxide (N(2)O) has been widely used since 1844, in recent years it has been implicated in a number of serious health hazards such as reproductive, nerve, liver, and kidney disorders. The National Institute of Safety and Health (NIOSH) recommends a limit of 25 ppm for chronic exposure to N(2)O in the dental office. Our study monitored ambient N(2)O levels in the dental office. N(2)O levels were compared for procedures performed in open clinics and private operatories as well as with and without a gas-scavenging system. Measurements were taken in the Dental Breathing Zone (DBZ) and Dental Chair Foot (DCF) at regular intervals. A four- to eightfold increase in average N(2)O levels was noted in the DBZ for unscavenged versus scavenged procedures. A three- to fourfold increase for unscavenged versus scavenged procedures was similarly noted in the DCF. N(2)O were significantly higher in private operatories than in open clinics, due to limited room volumes and in the DBZ over the DCF, due to mask leakage and increased oral exhalation. Scavenged N(2)O levels for both operatory types did not meet NIOSH guidelines. In contrast to previous studies using any form of gas removal, our study shows a significant decrease in N(2)O level achieved with an adequate scavenger system. With only four states regulating the use of N(2)O, and with concern over its deleterious effects growing, additional states and the federal government are expected to enact legislation regulating the use of N(2)O in the near future.
Esthetic restorative materials require a bonding procedure in order to be durable and reliable. I... more Esthetic restorative materials require a bonding procedure in order to be durable and reliable. In order to accomplish this ideal, the bonding system must be biocompatible, bond indifferently to enamel and dentin, have sufficient strength to resist masticator forces, have mechanical properties close to those of tooth structures, be resistant to degradation in the oral environment and easy to use. This paper reviews the published literature on direct and indirect adhesive restorative materials.
This article compares the bleaching efficacy of a combined at-home and in-office system with that... more This article compares the bleaching efficacy of a combined at-home and in-office system with that of an in-office system alone. Twenty people participated in the study. Ten of these participants were treated with an in-office 35% carbamide peroxide bleaching product in 2 visits of 15 minutes each. The remaining participants were treated with a combination at-home and in-office system that included a 15% carbamide peroxide at-home bleaching agent. After 5 days of treatment, the participants using the combination system demonstrated increased tooth whitening compared to those using the in-office system alone. Based on the sample size (20 patients), statistical significance was achieved.
A randomized, single-center, double-blind, parallel-group, placebo-controlled trial evaluated the... more A randomized, single-center, double-blind, parallel-group, placebo-controlled trial evaluated the whitening efficacy and safety of 2-week, twice-daily use of a 5.3% hydrogen peroxide tooth-bleaching gel delivered on polyethylene film. Efficacy was based on change in Vita shade scores from baseline to the end of treatment. Thirty-three patients in each group completed treatment. Use of the peroxide-containing gel led to a mean change in baseline Vita shade score of -3.70 +/- 0.35, compared with a change of -0.87 +/- 0.24 after use of a placebo gel. After adjustment for baseline scores, the mean difference in shade change between the peroxide gel-treated group and placebo-treated group was -2.85 +/- 0.41 (P < 0.0001). Both treatments were generally well tolerated. The strips offer ease of use, comfort, and shorter duration of wear compared with other at-home bleaching systems.
Objective: The objective of this study was to evaluate the effect of a dental water jet on plaque... more Objective: The objective of this study was to evaluate the effect of a dental water jet on plaque biofilm removal using scanning electron microscopy (SEM). Methodology: Eight teeth with advanced aggressive periodontal disease were extracted. Ten thin slices were cut from four teeth. Two slices were used as the control. Eight were inoculated with saliva and incubated for 4 days. Four slices were treated using a standard jet tip, and four slices were treated using an orthodontic jet tip. The remaining four teeth were treated with the orthodontic jet tip but were not inoculated with saliva to grow new plaque biofilm. All experimental teeth were treated using a dental water jet for 3 seconds on medium pressure. Results: The standard jet tip removed 99.99% of the salivary (ex vivo) biofilm, and the orthodontic jet tip removed 99.84% of the salivary biofilm. Observation of the remaining four teeth by the naked eye indicated that the orthodontic jet tip removed significant amounts of calcified (in vivo) plaque biofilm. This was confirmed by SEM evaluations. Conclusion: The Waterpik dental water jet (Water Pik, Inc, Fort Collins, CO) can remove both ex vivo and in vivo plaque biofilm significantly.
The effects of nitrous oxide (N2O) on steady-state concentrations and turnover rates of catechola... more The effects of nitrous oxide (N2O) on steady-state concentrations and turnover rates of catecholamines in the olfactory bulb, hypothalamus, brain stem, hippocampus, striatum, thalamus, cerebral cortex, and spinal cord were determined in rats. Animals were exposed for 2 h to either 60% N2O or air. Immediately following exposure, all animals were injected intraperitoneally with alpha-methylparatyrosine (alphaMPT), a competitive inhibitor of tyrosine hydroxylase, and sacrificed at 0, 30, or 90 min postinjection. Brain catecholamine concentrations were determined using high-performance liquid chromatography coupled with electrochemical detection (HPLC-EC). Results indicate that N2O exposure significantly elevates steady-state concentrations of norepinephrine (NE) in the hypothalamus and striatum yet decreases amine levels in the brain stem region. Steady-state levels of dopamine (DA) were not significantly altered in any region of the CNS by N2O exposure. Acute exposure to N2O also resulted in significant decreases in the turnover rate of NE in the brain stem, yet it increased turnover of this amine in the olfactory bulb, hypothalamus, and striatum. Acute exposure to N2O resulted in a decreased turnover rate of DA in the hippocampus and striatum. In contrast, N2O appears to increase DA turnover in the olfactory bulb. These results indicate that acute exposure to N2O in rats causes region-specific alterations in steady-state levels and turnover rates of DA and NE within the central nervous system.
Acrolein was examined as an alternative fixative to formaldehyde for immunocytochemicab localizat... more Acrolein was examined as an alternative fixative to formaldehyde for immunocytochemicab localization of neuropeptides in the rat brain. A brief (5 mm) vascular perfusion with a 5% acrolein solution allowed the identification of thyrotropin-releasing hormone (TRH), vasoactive intestinal peptide (VIP), somatostatin (SRIF), neurotensin (NT), methionine enkephalin (Menk), adrenocorticotropic hormone (ACTH), tyrosine hydroxylase (TH), and luteinizing hormone-releasing hormone (LHRH) in fibers and pen
Compendium of continuing education in dentistry, Jul 1, 2010
Questionnaires that focus on the fear of dental treatment typically include a narrow list of prev... more Questionnaires that focus on the fear of dental treatment typically include a narrow list of previous treatment-related factors. By omitting items concerned with psychologic, emotional, and interpersonal traits that impact treatment, practitioners often fail to gain additional valuable information on related anxiety issues. This study was undertaken to identify previously unrecognized or poorly discussed sources of fear and anxiety in patients seeking esthetic dental treatment. The Esthetic Clinic at Tufts University School of Dental Medicine recruited 62 participants who were asked to score their level of anxieties and concerns based on 24 different items on a 0 to 5 Likert scale. In addition, age, gender, and type of procedure in consideration were the only other variables recorded. The item that elicited the highest level of anxiety was &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;not feeling happy with my new smile.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; Thirty-eight respondents (61.3%) said they feel &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;markedly anxious&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;severely anxious&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; or answered &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;avoid completely.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; Concerns &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;that the outcome might look false and unnatural&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;that the dentist might not redo it if I am not satisfied with the outcome&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; both received 37 out of 62 (59.7%) similar responses. These results suggest obstacles to treatment exist not only in areas typically investigated but also in factors rarely discussed during the patient-practitioner encounter. The practitioner needs to consider a broader range of issues when addressing the patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s concerns.
Many studies have indicated that nitrous oxide (N2O) exposure results in specific effects on the ... more Many studies have indicated that nitrous oxide (N2O) exposure results in specific effects on the reproductive system, some of which are antigonadotropic. The neurochemical events regulating the pituitary-gonadal axis are probably influenced by N2O, but precise documentation is lacking. The effects of exposure to 30% N2O in air on the brain tissue concentrations of luteinizing hormone releasing hormone (LHRH), substance P (SP), met-enkephalin, and beta-endorphin and on beta-endorphin concentrations of the pituitary gland are described in this study. Female rats were exposed to either N2O or air for 8 hr a day over one estrous cycle, and the brain and pituitary tissues were collected and processed. Neuropeptide concentrations were measured by specific radioimmunoassays. Exposure to N2O resulted in significant elevation of LHRH in the preoptic area, with a concomitant decrease in SP. The SP concentration of the medial basal hypothalamus was significantly elevated in N2O-exposed animals. Exposure to N2O resulted in significant increases in met-enkephalin in the brainstem area and beta-endorphin in the pituitary. These results suggest that exposure to N2O alters the interactive neural system activity regulating gonadotropin secretion from the pituitary. The significance of increased met-enkephalin in the brainstem of N2O-exposed animals is not known.
The increasing demand for esthetically pleasing results has contributed to the use of ceramics fo... more The increasing demand for esthetically pleasing results has contributed to the use of ceramics for dental implant abutments. The aim of this study was to compare the biological response of epithelial tissue cultivated on lithium disilicate (LS2) and zirconium oxide (ZrO2) ceramics. Understanding the relevant physicochemical and mechanical properties of these ceramics will help identify the optimal material for facilitating gingival wound closure. Both biomaterials were prepared with 2 different surface treatments: raw and polished. Their physicochemical characteristics were analyzed by contact angle measurements, scanning white-light interferometry, and scanning electron microscopy. An organotypic culture was then performed using a chicken epithelium model to simulate peri-implant soft tissue. We measured the contact angle, hydrophobicity, and roughness of the materials as well as the tissue behavior at their surfaces (cell migration and cell adhesion). The best cell migration was o...
More important than any resin cement is the marginal fit and retentive nature of the ceramic rest... more More important than any resin cement is the marginal fit and retentive nature of the ceramic restoration to be bonded. Cementation should not be intended to compensate for poor dentistry, but to assist in producing superior aesthetic results. Responding to the demand for all-ceramic restorations, dental manufacturers continue to refine the resin cements used in luting for this modality. The ideal resin cement for ceramic restorations must demonstrate low viscosity; easy loading; a film thickness which facilitates complete seating high strength; and excellent wear resistance. This article reviews the available resin cements, with particular focus on a new type of initiator and stabilizer for light- and dual-cured resin cements.
The purpose of this study was to compare the wear, cement margin breakdown and bond strength of r... more The purpose of this study was to compare the wear, cement margin breakdown and bond strength of restorations following 6 to 12 months of simulated use in vitro of the Sonicare and a manual toothbrush. Extracted molar teeth with Class V hybrid composite resin restorations (n = 21) or with Class V gold inlays cemented with zinc phosphate cement were tested for wear and marginal integrity following brushing for a period that simulated 6 months of typical use. One-third of the molars in each group were brushed with the Sonicare and one-third were brushed with the manual brush. The remaining third served as non-treated controls. Toothbrushing was performed under a standardized load using a piston-action brushing machine. After brushing, the enamel, dentin/cementum and restorations were examined by light and scanning electron microscopy. There was no apparent wear of tooth structure or of restorative materials with either the Sonicare or the manual brush. There was a small loss of cement ...
Twenty-two family practice dentists, in a large metropolitan area, were recruited to act as indep... more Twenty-two family practice dentists, in a large metropolitan area, were recruited to act as independent examiners in a study to evaluate the compliance of their patients to accept a good oral hygiene regimen with the use of a fluoride dentifrice, containing hydrogen peroxide and baking soda, dispensed from a dual dispensing package. To evaluate compliance, the dentists attended an orientation seminar and were trained to assess gingival health using the CPITN periodontal probe. Each dentist evaluated the gingival health status of five to seven of his own patients, initially and after one and three months of product use following hygiene instruction and product assignment. One-hundred and thirty-one patients successfully completed the study. After one month of using the hydrogen peroxide/baking soda toothpaste, the mean reduction in bleeding sites was 53%; at three months the reduction was 62%. The hydrogen peroxide/baking soda dentifrice was well accepted by dentist and patient, and ...
Uploads
Papers by Gerard Kugel